The basic model for completing a telephone call is changing. Rather that rely completely on end to end circuit switched connections, more and more phone calls are completed using, at least in part, packet switching techniques. More systems and equipment are being developed that are dedicated to transmission of voice communication on the Internet. As more of these systems and equipment become available, the complexity of the communications matrix increases.
In IP telephony systems it is known to conduct a telephone call utilizing a combination of public switched telephone network (PSTN) links, and packet telephony links. An example of such a system is shown in U.S. Pat. No. 6,404,864 (“the '864 patent”) owned by the assignee of the present invention. In such prior systems, an “originating gateway” takes the call from the PSTN to the Internet, and a “terminating gateway” places the call back onto the PSTN at a remote location after removing it from the Internet. Thus, a long distance call may have three “legs” a first PSTN leg from the calling telephone to the originating gateway, a second leg from the originating gateway to a terminating gateway, and a third leg from a terminating gateway to a called telephone.
The '864 patent is directed to a system that helps the originating gateway pick which of several terminating gateways that are located in the remote location should be selected to complete the call from the Internet, over a PSTN link, to a destination terminal. The '864 patent is incorporated herein in its entirety by reference.
Of course, not all terminating gateways are equal; some are more desirable than others on the basis of their speed, their cost economy, or their connection quality. Thus, to optimize the overall efficiency of the transmission operation, a system preferably should select a routing based on pre-established criteria, some of which are noted above.
Typically, there is a set of rules that gets executed in the system in order to ascertain the appropriate terminating gateway or other routing to use. These rules are executed for each call, and are often executed at an intelligent server that is remote from both the originating gateway and the terminating gateway. Therefore, there is additional communications overhead for the originating gateway to communicate with the intelligent server for each call. Often, the communications involves sending one or more parameters of the call (e.g. the called number) from the gateway to the intelligent node, executing some routing rules at the intelligent node, and returning a response that specifies one or more terminating gateways that can be used to complete the call. The terminating gateway takes the call from the Internet and completes it to a remote destination, usually using a PSTN link.
Of course, electronic equipment is subject to malfunction periodically. If a gateway experiences a breakdown or any malfunction, a call routed through this gateway will not be completed. It would be desirable to modify the established rules by which routing is set up involving any malfunctioning gateway in order to circumvent an inoperative route, thus the malfunctioning gateway is avoided. The present invention recognizes that implementation of corrective action through operator intervention will, of necessity, involve delays.
It is an object of the present invention to provide a system and method for call routing through a network while reducing the communications and processing overhead required for each call to be analyzed and for routing rules to execute and select a terminating gateway for each call.
It is a further object of the present invention to provide a system and method capable of modifying rules for routing a call to eliminate.
This and other objects of the invention disclosed will become more apparent from the description of the invention to follow.